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ASME 1331.3-2016 in accordance with para. 306.4.3 may be used under Table 308.2.1 Permissible Sizes/Rating Classes severe cyclic conditions. for Slip-On Flanges Used as Lapped Flanges (b) A fabricated lap to be used under severe cyclic Maximum Flange Size conditions shall conform to the requirements of para.306.4.1,except that welding shall be in accordance Rating Class DN NPS with para. 311.2.2. A fabricated lap shall conform to a 150 300 12 detail shown in Fig. 328.5.5, sketch (d) or (e). 300 200 8 (c) A flared lap is not permitted under severe cyclic conditions. GENERAL NOTE: Actual thickness of flange at bolt circle shall at least equal minimum required flange thickness in ASME 1316.5. 306.5 Fabricated Branch Connections The following requirements do not apply to fittings capable of removal from the valve, while the valve is conforming to para. 306.1. under pressure,by the removal of the stem seal retainer 306.5.1 General. A fabricated branch connection (e.g., gland) alone. made and verified for pressure design in accordance with para. 304.3, and welded in accordance with 308 FLANGES, BLANKS, FLANGE FACINGS, AND para. 311.1,is suitable for use in Normal Fluid Service. GASKETS 306.5.2 Fabricated Branch Connections for Severe 308.1 General Cyclic Conditions. A fabricated branch connection to be used under severe cyclic conditions shall conform to 308.1.1 Listed Components. A listed flange,blank, the requirements of para. 306.5.1, except that welding or gasket is suitable for use in Normal Fluid Service, shall be in accordance with para.311.2.2,with fabrication except as stated elsewhere in para. 308. limited to a detail equivalent to Fig. 328.5.4D sketch (2) 308.1.2 Unlisted Components. Unlisted flanges, or (4), or to Fig. 328.5.4E. blanks, and gaskets may be used only in accordance 306.6 Thermowells with para. 302.2.3. Thermowells shall comply with ASME PTC 19.3 TW 308.2 Specific Requirements for Flanges where applicable. See Appendix F, paras. F308.2 and F312. 307 VALVES AND SPECIALTY COMPONENTS 308.2.1 Slip-On Flanges (a) A slip-on flange shall be double-welded as shown The following requirements for valves shall also be in Fig. 328.5.213 when the service is met as applicable by other pressure-containing piping (1) subject to severe erosion, crevice corrosion, or components,such as traps,strainers,and separators.See cyclic loading also Appendix F,paras. F301.4 and F307. (2) flammable,toxic,or damaging to human tissue 307.1 General (3) under severe cyclic conditions (4) at temperatures below —101°C (-150°F) 307.1.1 Listed Valves. A listed valve is suitable (b) The use of slip-on flanges should be avoided for use in Normal Fluid Service, except as stated in where many large temperature cycles are expected,par- ticularly if the flanges are not insulated. 307.1.2 Unlisted Valves. Unlisted valves may be (c) Slip-on Flanges as Lapped Flanges. A slip-on flange used only in accordance with para. 302.2.3. Unless may be used as a lapped flange only as shown in pressure—temperature ratings are established by the Table 308.2.1 unless pressure design is qualified in accor- method set forth in ASME 1316.34,pressure design shall dance with para. 304.5.1.A corner radius or bevel shall be qualified as required by para. 304.7.2. conform to one of the following as applicable: 307.2 Specific Requirements (1) For an ASME B16.9 lap joint stub end or a forged lap(see para.306.4.3)the corner radius shall be as speci- 307.2.1 Bonnet Bolting. A bolted bonnet valve fied in ASME 1316.5, Tables 9 and 12, dimension r. whose bonnet is secured to the body by less than four (2) For a fabricated lap, the corner bevel shall be bolts, or by a U-bolt,may be used only for Category D at least half the nominal thickness of the pipe to which Fluid Service. the lap is attached (see Fig. 328.5.5). 307.2.2 Stem Retention. Valves shall be designed (3) For a flared lap see para. 308.2.5. so that the stem seal retaining fasteners (e.g., packing, 308.2.2 Expanded-Joint Flanges. A flange having gland fasteners) alone do not retain the stem. Specifi- an expanded-joint insert is subject to the requirements cally,the design shall be such that the stem shall not be for expanded joints in para. 313.